Halo is not ideal for your goals. You can only run it for a short time because it is quite liver toxic. So sure, for 3 wks you will be strong and then you come off and you'll return to a normal man haha. So think long term. Really, test is the base of all cycles and this will make you very strong. If you are not familar with it, start there. Just 400mg EW of test Cyp will give you intense strength gains. Gaining muscle is going to come down to nutrition. So if you dont want to get bigger or change your composition, then you'll need to keep food intake from being too high...but really, you could add muscle and then get rid of fat. That would make much more sense and you would be able to better maintain your strength. Unless you are in a meet that requires you to make a weight class, be open minded to getting some more lean muscle mass because it is only going to help your goals. You could add to your test some Var which is great for strength and can be used much longer than halo. If you wanted to do a var cycle, here is how I would lay it out, using less test than I suggested for a test only cycle. 

1-10

Test Cyo or E about 300mg EW

adex, dosed as needed, maybe .5mg 2-3x wk

1-8

Anavar 40- 50mg ED

Then PCT 2 wks after last shot of test