This can be hard to judge. I like to set it up so the top of the tension hoop (or, if your TH hoop has a notch, the top of the notch) is 3 -4 mm above the fingerboard - don't trim it yet - let it dry for 3 -4 days, then start tensioning up gradually ( a little at a time for about a week. With a little luck, it will start to come good when the top of the TH is about even or slightly below the FB. If it stretches more, well, you haven't trimmed it yet, so you can re-soak and start over. Every skin is different.

If your "tension gauge" is a drum dial, shoot for about 90, but with a skin head it will never be perfectly even all around.

Others might chime in, but that's my 2 cents.

Good luck with it.

Have you considered mounting the goat hide first - as a trial run before using the more costly calfskin? Just a thought...

Here is a link to information about what I do for my pre-mounted heads:  Crown Height

Setting the initial crown height is more art than science.  But the bottom line is - just mount the crown lower than where you want it to end up.  I'd say at least 1/16" - 3/32" - depending on how tight you mount the wet hide.  

Good luck!  I trust it will turn our well for you!

JB

If not you’ll hear from me!

The head went on easily without any creases on the first try and after 24 hours it has tightened up to about 75-80 on my gage. However, because the skin was wet I couldn’t see a “stripe” that ran through the surface pattern and I got it about 3 degrees off horizontal. So once it is fully dry can I rotate the head while on the banjo or can I just pull it and reinstall it at the new angle without messing it up? Thanks

Once dry the head is fairly rigid but you should be able to level it up somewhat by concentrating on tightening those hooks that will help level it first. Best to sit it on your lap looking at the side so you can keep it parallel as you tighten.
Everyone has their own method but I always take the head off after a day and trim the skin with scissors, cutting the waste while still in place runs the risk of scratching the inside of the stretcher band.

I forgot to say that I make a reference mark where the head is with a pencil so that when refitting it goes back in same position because most old banjos can be out of round slightly

Thanks, but I was referring to a straight line pattern in the head surface, probably where the skin was above the backbone, which I would prefer to line up with the strings whereas now it is about 3 degrees out of that line. It sounds as though you are saying I can remove the skin and just turn it 3 degrees and then pop it back down.

Yes you can remove it once it's dry.  And put it back on at a different orientation so long as the banjo is sufficiently round.

The method Richard and I use involves removing the head entirely and trimming the extra skin with scissors.  So that shows how tough they are once dry.

I like that method because I can see how much it tightens up when dry, and if I don't like it I'm able to re-wet and re-mount.

Thanks, exactly what I needed to know. The down side is I have to remove all those darned j hooks. Maybe I’ll just loosen them and then see if I can slide the skin a bit. But I like the idea of removing it and trimming the excess with scissors, just to make sure I don't nick the head itself. 

I ended up removing the tension hoop and the head then trimmed it with some bandage scissors. Came out straight and clean with no knife scratches on the inside of the tension hoop like you get using an Xacto knife or razor blade, plus no chance of nicking the head. I probably could have gotten the cut edge a bit lower but it was my first ever skin head so I erred a bit on the safe side. I can’t believe how easy this was, especially after the various YouTube videos. One gal trashed 3 heads before she got one on, so I was a bit more cautious than might have been necessary. Anyway once I see how this one sounds and holds up under our soggy North Carolina humidity, I may go ahead and install skin heads on my other banjos. As always, thanks for the help.