Dryland training: Freestyle Catch on Vasa Ergometer

There are many drills to work on the freestyle catch and thru trial and error you will find the best ones for your current functional ROM in the shoulders and level of fitness. The Vasa Ergometer http://vasatrainer.com/ is a great tool for this. Set the Damper Door setting on Level 1 and practice the freestyle pull pattern slowly, focusing on the setting your catch about shoulder width. A good visual cue for this is the pulley's that the paddles run through on each side of the Erg. This may help with your arms crossing over center as well by having an entry point about shoulder width. Keep a firm wrist, fingertips pointing at the floor and a straight line from finger tips to elbow. This needs to occur before applying power and fully engaging your lats. You will notice my heading moves side to side and I find doing this form time to time helps me stay focused setting my "catch" because I am watching my hands/forearms before starting the pull.  

Two additional drills to try:
1) you can isolate arms by doing a single arm drill leaving the non-pulling arm in the extended/forward position.

2) pulling both arms at the same time think butterfly pull or pulling yourself out of the pool. Plus, you can set up the Erg monitor to view/measure your power (Watts) for each arm. 

To transfer to the pool, I have found a very simple drill I got from Marc Evans works great, single arm swimming using a kick board. With your head out of the water, start stroking with one arm while the other arm is fully extended on top of the kick board. This lets you first see the entry point width, before you set the catch and then pull. Trying doing a 25 (1/2 of each arm) then swim a 50 to reinforce the drill. Repeat this sequence 4-6 times as part of warm up or integrate into main set. 
Good Luck!