Increasing caster doesn't put more weight on the front end but I increased the caster as much as I could. I pressed the bushings out a little on the arms to offset them and shimmed with 12mm washers, better fit than 1/2". I made shims for the upper ball joint and used washers for spacers on the bottom for the shock. I am a little under 3*. I wish I could get 5 or 6 but you can only get so much with the trunions. Initially it was darty at 65mph with what I set the toe at. I reduced the front and increased the rear toe. Basically an Elise alignment. It is one hand stable at any speed. It is hard to stay under 90 on the freeway.
I'll give you tmi as you are going to end up more tail heavy than stock too.. I don't know what your intentions are when finished, track or just a fun weekend car but I wouldn't worry too much about the weight balance unless you are building a competitive car that pays. I've read an S2 Europa is 45/55. Some say 40/60 to 42/58 is perfect. A Porsche GT3 RS is 39/61. A Lotus Elise is 38/62. I think I am 36/64 with no one in the car, I would have to check my notes. I used the 38/62 for brake set up and springs as my wife is my partner in crime and is always in the car with me so the weight is a constant. If you end up too tail heavy, set it up with a little more understeer and never fully lift going into a turn. Start slower and get used to keeping on the pedal after you brake. I did my springs based on weight and ended up making an adjustable 7/8" front bar for a little more push. I run a 205 tire front and 245 tire rear. My rear track is a little wider than a stock Europa too. On an autocross coarse it now has a little low speed push. It will only oversteer if I fully lift in a turn. It would be faster with less push but it's not worth the risk for me.
Torque wise you will probably be about the same as mine. I wouldn't want any less weight on my rear. Traction with regular Europa sized tires and the short wheel base is imo not the safest. Look into 200 tread wear tires when the time comes. The 200's are designed for the SCCA autocross minimum tread wear and have the best cold grip other than a Hoosier A7. R88R's (100tw) if your are on 13's.